Bicycle ergometer



June 13, 1950 v, GUlLLEMlN, JR 2,510,973

BICYCLE ERGOMETER Filed July 12, 1945 Patented June 13,1950

UNITED STATES PATENT OFFICE BICYCLE ERGOMETER Victor Guillemin, Jr.,Dayton, Ohio Application July 12, 1946, Serial No. 683,195 Claims. (Cl.i3-381) (Granted under thev act of March 34, 1883, as amended April 30,1928; 370 O. G. 757) rIfhe invention described herein may bemanufactured and usedby or for the Government for governmental purposeswithout payment to me of any royalty thereon.

Thisinvention relates toa frictional braking dynamometerV device fordetermining the amount of work doneor energy expended during exercise bya human subject operating the device.

v The need for a device of this kind arose in connection with researchdirected toward reducing 2v` A further object of my invention is toprovide a bicycle ergometer device having a foot propelled freelyrotatable rear wheelwith a smooth flat periphery in which a bandfrictionally engages the wheel periphery and has ends partially passingin opposite directions around an indexed drum rotatively supported by `alever arm adjustthe incidence of aeroembolism (bends) in flying ,A v

personnel on high altitude missions. The bends, which frequently causepain of suicient intensity to seriously reduce the eifectiveness of yingpersonnel, were thought to be caused by bubbles of nitrogen forming inthe blood at high altitudes. The bubble formation may be prevented byremoving the nitrogen from the flyers body before he goes on a mission.This so-called denitrogenation may be accomplished by allowing the flyerto breathe pure oxygen for a suitable period before the ascent, and theprocess may be hastened by allowing him to exercise, thus increasing therate and depth of his breathing. To get the desired results, it wasconsidered to be necessary to measure and control the rate of work doneduring this exercise.

. It was found that there was no device available that was suitable forthe above purpose, and the apparatus, which is the subject of thepresent invention, was therefore developed. In addition to its originalpurpose, this bicycle ergometer has been used in various aeromedicaldevelopment projects where it is necessary to measure human workperformance. It has been used, for example, to give a measured work loadto flying personnel in altitude chambers during tests of oxygenregulators, in order to determine Whether their oxygen delivery isadequate to take care of the work required in the performance of ablypivotally mounted on the bicycle frame, the indexed drum being springbiased in one rotative direction with the indices inregistering relationwith a pointerof the lever arm such that adjustment of the pivoted leverkarm varies the band tension and rotation of the wheel produces adiiierence in tension in the ends of the band which difference actuatesthe indexed drum against the spring bias to register Vthe net tangentialforce acting on the wheel periphery denoting work performance. 1

. Other objects and advantages will be apparent as the description.proceeds taken in conjunction with Vthe accompanying drawing whereinfor the purpose of illustration IV have shown a simple preferredembodiment of my invention in which:

v Fig. 1 is a sideelevational view of the bicycle ergometer;

Fig. 2 is an enlarged cutaway View, partly in section, of the dierentialforce meter as suspended in the bicycle frame; and

y Fig. 3 isa cross section taken on the line 3--3 of Fig. 2, looking inthe direction of the arrows.

k Referring particularly to Fig. 1 there is shown a bicycle frame,generally referred to by the reference character Il), having handlebarsII and a seat I2 mounted thereon in the usual manner. The front fork I3diverges downwardly to act as a front support 4for the bicycle frame.Rear fork flight duties. Many other uses will become apparent as thedescription proceeds. y

The principal object of my invention is to provide a frictionaldynamometer device in which a sin-gle differential force meter measuresthe net tangential force between the frictional co-actng elements.

Another object of my invention is to provide a bicycle frame arranged torest in a stationary upright position having a foot propelled rear wheelwith a smooth periphery in frictional engagement with a band passingsubstantially therearound having ends connected in opposed relation to asingle differential force meter means that indicates the net forceexerted on the propelled wheel bythe drag of the band.

members III and I5 intersect at I 6 and are attached to diverging rearsupporting stands Il.

A wheel 20 rotatively mounted on an axle 2|- fixed at the frameintersections I6 is of a diameter to substantially clear the supportingsurface for the .bicycle frame I0, vand has a smooth flat periphery 22which acts as a brake drum. The wheel 20 is rotatively propelled in aclockwise direction, corresponding to the forward locomotion of abicycle, by a foot operated opposed crank means 23 journaled at theintersection of the frame bars 24 and 25 as is of usual bicycleconstruction. The [crank means 23 has a sprocket 26 xed thereto totransmit rotary motion to a `sprocket 21 fixed to the Wheel 20 through achain 28 inthe ordinary manner of bicycle rear Wheel propulsion.

Asbest seen in Figs. 2 and 3, there is a differential force meter,referred to generally by the vlreference character 30, adjustablypivotally mounted on the bicycle frame |U. The differential force meter30 includes a lever 3| having a bifurcated end with arms 32 and 33straddling one extension of the fork member |4 and pivotally supportedthereon as by a bolt 34. A right hand threaded bolt 35 having a knurledhead portion 36 journaled in an opening 31 of an extension 38 on thefork member I4 above the bolt 34 cooperates with a threaded opening 39in a nut 4011 pivotally mounted by journal extension portions 4| in thearms 32 and 33 of the biiurcated portion of the lever 3| to cause arotation. of the lever 3| about its pivot 34 upon rotation of the bolt35. A drum 42 is rotatablymounted onthe end of the lever 3| opposite itspivot byv elf-journaling means illustrated herein as a bolt 43 snuglytted in a bore through the lever 3| andloosely passing through a centraljournaling opening of the drum 42 in a well known manner. Where it. is.desirable to obtain. a very high` degree of accuracy of indicated Workload` a frictionl'essf type bearing means may. be employed. between thebolt 43v and the drum. 42. The drum has-an endsurface. 44Iwith indices45-reading from 0' to 90 which, in. this instance, represents the workload in foot-pounds. Theindi'ces- 45are arranged around the drum 422mindicative cooperation with a pointer 46 'that'.is'. integrallwiththelever 3|. The drum 42'isbiased ina counterclockwise directionV by'aspirali spring 4'1f that is attachedi on its innerend to thelever 3| bya stud 48iandonits outer end to the drum 42 by a stud 49. The drumnormally rests withthe-Oat the pointer- 46, the counterclockwiserotation being arrested byl alug )l (see Fi`g..3r)`` on the drum 42engaging a similar lug` 5L on` the lever 3|.

A band 52, consisting of metal orfabr-icf tape. or other desirablematerial, has an end 53 passing a very' short distance clockwisearoundthe periphery of the drum- 42 and fastened thereto as byarivet'meansr54i. The'band 52 passessub-v stantia-lly around the wheelbeing infrictionalY engagement with the` smooth flat periphery `22thereof and has its opposite end 55 passing-counterclockwisesubstantially around the periphery of the drum 4'2- inv sideby-'sidevrelation to the end 53 and fastened theretoasbya rivetmea-ns 551 The end55 mustbe fastened asfar around the drum 42 as possibleI to permit' afull scale read'- ing on the drum yet-the endl 55 must not be sopositioned as to'ride under'the band 52 contact-A ingthe drumtangentially `to altertheworkable lever arm;

The' spiralspring 41 is-of astrength, and the: wheel size and number ofturns per pedal turn' is'so calibrated and arranged that a' directreading may betaken infoot-pounds per pedall turn. Or, if thepedals-areoperated at a predetermined rate, as for example by peda-lingVinA time 'toa metronome; the reading maybetakendirectly` in--foot-pounds per second or calibrated` directly in horse-power.

In operation', the human subject'mountsthe bicycle ergometer'in likemanner-'asmounting'an ordinary bicycle. The subject, upon pedaling'in'the forward direction, will' causethe wheel 2|lt'orotate clockwiseand'frictionally dragthe bandY 52" with it. The two ends of'thebandl 5Tbeing'connected to the differential force meter in opposed relationpermits the tensionson the two endsto mechanically evaluate thedifference in forces or produce the net force on the drum 42 to be readfrom the single differential' force. meter dial 45, 4'6.. The frictionof. the band' 52;onthe periphery 22of' the'wheelA 20' causes the tensionin the endY 55 to exceed that in the end 53, thus rotating the drumuntil the increased backward torque of the spiral spring 41 justbalances the excess pull of the end 55, whereupon rotation of the drum42 ceases at which time the work in foot-pounds will be registered bytheindices 45 with relation t0 the pointer 46.

The work load may be varied by adjustment of the bolt 35 to vary thetension on the band 52. By turning the knurled head 36 clockwise thelever 3|l will be rotated counterclockwise about its pivot stretchingthe band 52 tighter about the periphery 22 of the Wheel 20 which willincrease the net tangential force applied to the wheel and thus increasethe work load which will be registered on the differential force meter30 when the wheel 20 is'being rotated clockwise.

Upon termination of operation of the bicycle ergometer the spiral spring41 will return the drum 42 to its normal position' of registering 0, theband 52' slightly rotating the wheel 20 in the reverseV direction until'the lug 5U is stopped bythe lug 5|. The rotation ofthe Wheel 20 in thelreverse direction will cause noinjury to the device since the lugs 5l)Iand- 5| prevent any reverse injurious rotation ofthedrum 42 and thewheel 20 would merely slip in the-band 521'.

From the foregoing itV may' be seen that this bicycle ergometer is auseful contribution to the art of determining the power output of humansubjects. While I have shown` and described a single specific embodimentof this invention it is tovbe understood that other modifications andfand scope of my invention.

I'4 claim:

1. A bicycle ergometer assembly for measuringA thev work output of humansubjects per pedal turn comprising; a' bicycle-like framel arranged torest in a stationary upright position; a wheel havingl a smoothperiphery'rotatablymounted in said `bicycle-like frame; a lever memberpivotally mounted on one end` to the bicycle-like frame, said levermember being ada-ptedto swing through an arc in which the free endIthereof varies relative to the axis-of said wheel; adjustable means forrotating said lever member througlrsaid arc; a differential' torqueresponsive meter meansincluding'an indexed member movably mounted'onsaidlever member and being biased inA one directionof movement; and a bandpassing partially around thesmooth periphery of said'wheel'andhavingtwoends connected to said indexed member in'suclr'a4 manner as to applyforcesto moveV said indexed member respectively ihr-'oppositedirections, the resulting net force moving said indexed member againstits bias to an extent proportional to the frictional forceof said bandon said wheel periphery'upon forward rotation of said' wheel" whereinwork proportional tothe movement of saidindexed member is perormed inVaccordance with the tension placed on said band by' said adjustablemeans.

2. In a dynamonieter device, a wheel having a smooth flat peripheryadapted to be propelled; a diierential torquev responsiveY meter meansincluding a supporting member in adjustable relation with sai-d wheel onwhich is rotatably mounted an indexed' drum member internally biased inone rotative direction, a band passing partially' around: theperipheryofsaid: 'wheel and'` having its two ends Iconnected to said indexed drummember about the' periphery' thereof in opposed relation sov asto applytorques tending to move said indexed drum member respectively 1inopposite rotative directions, the resulting net torque arising fromfrictional tension of said band upon rotation of said wheel rotatingsaid indexed drum member until the bias of said indexed drum memberbalances the resulting net torque, the adjustment of said supportingmember relative to said wheel being adapted to vary the tension of saidband for changing the net torque on said indexed drum, and said indexeddrum member being calibrated in work units to directly indicate the workdone by a predetermined rotational movement of said Wheel.

3. A bicycle ergometer assembly for measuring the work output of humansubjects comprising, a bicycle-like frame arranged to rest in astationary upright position, a wheel having a smooth at peripheryrotatably mounted in the rear fork of said bicycle-like frame andadapted to be rotated by foot-operated means, a single differentialtorque responsive meter including a spring biased indexed drum rotatablymounted on a lever arm pivotally attached to said bicyclelike frame,said indexed drum being calibrated to register directly foot-pounds ofwork done per pedal turn of the ergometer, a band passing substantiallyaround the smooth flat periphery of said wheel |with its two endspassing partially around said indexed drum in opposite directions andfastened thereto, an adjusting means associated with said bicycle-likeframe and said lever arm to rotate said lever arm about its pivot forvarying the tension of said 'band whereby the operation of the footoperated means to rotate said wheel will frictionally force said band ina direction to rotate said drum against the bias of said spring untilsaid spring Ibias balances said frictional force, and the balancedposition of said indexed drum indicating the frictional tension of saidband from which the work done per pedal turn may be deduced.

4. In a bicycle ergometer assembly for measuring the work output ofhuman subjects in which there is a bicycle-like frame arranged to restin a stationary position and having a foot propelled wheel with a smoothperiphery associated therewith, the improvement comprising; a singledifferential torque responsive meter including an indexed drumrotatively mounted on a lever and spring biased in one rotativedirection, said lever being pivotally mounted to the bicycle-like frame,a band passing substantially around the wheel frictionally engaging theperiphery thereof and with its ends passing partially around saidindexed drum in opposite directions and fastened thereto, an adjustingmeans associated with said bicycle-like frame and said lever to rotatesaid lever about its pivot for varying the tension of said band wherebywheel rotation will cause a difference of tension at the ends of saidband, the net tension being in opposition to the spring bias of saidindexed drum to rotate said indexed drum by an. amount proportional tothe net torque, and said indexed drum being calibrated in work units todirectly indicate the work done by a predetermined rotational movementof said wheel.

5. In a bicycle ergometer assembly for measuring the work output ofhuman subjects in which there is a bicycle-like frame arranged to restin a stationary position and having a foot propelled wheel with a smoothnat periphery associated therewith, the improvement which comprises; asingle differential torque responsive meter including a lever arm with apointer integral therewith pivotally mounted on the bicyclelike frameand rotatively supporting a spring biased indexed drum, the indices, ofsaid drum' being arranged in cooperative indicating relation withrespect to said pointer, a band passing substantially around said wheelin cooperative frictional relation with respect to the smooth atperiphery thereof and having its two ends passing partially around saidindexed drum in opposite directions and fastened thereto, a screwadjusting means associated with said bicycle-like frame and said leverarm for rotating said lever arm about its pivot to vary the tension ofsaid band whereby varying the band tension will Vary the torque loadconditions upon wheel rotation which torque load will be indicated onsaid differential torque responsive meter, and said indicated torqueload being directly proportional to the friction force of said band onsaid wheel periphery and therefore indicative of the work done perrevolution of the ergometer foot propelled wheel.

VICTOR GUILLEMIN, JR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 403,995 Gilman md- May 28, 1889562,198 Robinson June 16, 1896 2,238,295 Snyder Apr. 15, 1941 FOREIGNPATENTS Number Country Date 12,056 Great Britain A. D. 1897

